89 supra runs good when cold but like crap when hot.

[rap2chin]

Hey I got an 89 supra turbo. It runs. Very good when cold. But once it warms up it starts boggin out.
I noticed my coolent temp sensor is disconnected and the check engine light reads code 22
(Coolent temp sensor signal). I don't know where the wires go or what color they r cuz they were ripped out. So would the car run like crap becouse of that sensor

 

[89supra7mgte]

if it the ecu input sensor i think it might have an issue when at operating temp. Ecu is seeing a default reading either extremely cold or hot, which will possibly cause car to stay in open loop which may be adding too much fuel causing rich condition.

Also ran in to vac leaks that would only show up when car got hot, metals expanding and such, you can always try shooting some carb clean around manifold, tb and such.

 

[Nick M]

The coolant temp sensor is a NTC type. That means resistance goes down as temps go up by design. So unplugged is the same as high resistance and reads cold. So voltage the ECU reads would be high, because it needs as much voltage as possible to overcome the resistance. It isn't a return signal like a TPS or VAF meter. The ECU looks at voltage between the pull up and E2 ground. When hot, there is very little resistance so voltage needed to overcome is lower. Now that we have that out of way, lets move on. Fix the wiring and then come back.

Because when the ECU detects the open, warm temps are substituted. So the sensor isn't your problem. But the rich condition when cold helps your real problem.

 

[rap2chin]

Ok great thanx guys. Now what is the coloring for the wires for the coolent temp sensor. And can u take a pic and show me where the ecu input or whatever is located. And. Yes it runs rich. And yes so far I replaced all vacum lines. Thank u

 

[89supra7mgte]

I believe the gauge is in the middle of the coolant housing (backside of t-stat) has green connector, with two wires one brown and one solid green iirc

 

[rap2chin]

allright so i think i got it took me w while but ( THE CAUSE FOR MY CAR RUNNIN RICH AND THE WAY IT WAS. IS THE CAR HAS COLD START INJECTOR WHILE THE COOLENT TEMP SENSOR IS DISCONNECTED AND WHILE THE CAR IS COLD THE CAR RAN FINE THE REASON IT RAN LIKE IT DID IS, ONCE THE CAR GOT HOT THE COMPUTER KEPT DUMPIN EXTRA FUEL IN THERE THROUGH THE COLD START INJECTOR RESULT IS CAR RAN RICH AND LIKE CRAP. SO GOT A NEW SENSOR WIRED IT IN. BUT THE ONLU WIRES THAT I FOUND IN THAT AREA THAT WERE GREEN AND BROWN WERE COMMIN OFF OF THE MASS AIR FLOW SENSOR DONT KNOW IF THOSE ARE IT BUT MADE THE CAR RUN GREAT NO BOGGIN OUT NO LAG NOTHIN. ARE THOSE CORRECT WIRES TO CONNECT TO? NOT SURE LET ME KNOW. BUT ALSO BEFORE I FIXED THAT. THIS IS A SECOND PROBLEM... READY ? MY ANTILOCK LIGHT COMES ON THEN OFF. WHEN IT COMES ON MY STEERING GETS TIGHTER WHEN ITS OFF ITS BACK TO NORMAL WHY WTF!! LITTLE HELP PLEASE?

 

[jetjock]

What's with all the caps?

1) With the coolant sensor disconnected the computer will think the coolant is hot.

2) Wire colors for the sensor are easily found by looking in the TEWD.

3) The cold start injector can't operate unless the engine is cranking.

 

[jrot]

my wires were brown and green and came from loom near my afm...and i had the exact same issue...sounds like your on the right track from my experience.....ill get a pic later as im stuck at work......

 

[hvyman]

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=48

Should be solid green wire. There is 1 sensor for the gauge and 1 for the ecu.

The yellow(dirt makes it brown) and green is for the gauge.

 

[CyFi6]

What's with all the caps?

1) With the coolant sensor disconnected the computer will think the coolant is hot.

Care to explain why? Only way this is possible is if the computer would fail-safe to hot, which doesn't make any sense to me.

 

[rap2chin]

jrod the pic would help ALOT. hvyman thanx for the diagram to me when i look at it. it looks like japanees since im not big on wiring but i got to make something of it.. but like any other time all the help i can get ill appreciate. so thank u all.. this is my last step for my supra to run like a champ!

 

[jetjock]

Care to explain why? Only way this is possible is if the computer would fail-safe to hot, which doesn't make any sense to me.

It does fail safe to hot (80 C), as it should. After all hot is the normal operating condition. Furthermore, this occurs with either an open or shorted sensor.

 

[rap2chin]

jrot him me up e-mail me rap2chin@gmail.com with ur number or ill give u mine. it be easier if u could walk me through i been workin on this for months. im ready to be done

 

[jrot]

i didnt make it home before dark and remembered that i made my own loom for it so all my wires are blue now but shoot me a call and ill help you out as best i can...and ill put up a pic anyway just so you can see where the wires came from in the morning when i get some light...i emailed my # to you...

 

[Nick M]

Care to explain why? Only way this is possible is if the computer would fail-safe to hot, which doesn't make any sense to me.

The only reason to ever run "cold" is because it is easier to vaporize fuel when hot than when cold. So it is run richer when cold to keep it easy to light. Leaving it a little richer would only give you a little worse milage.

 

[rap2chin]

ok so thanx to all of ur help. i have succeeded so thanx now my Supra starts with no problem dont have to keep hitting the gas to get it started. so now it just starts rite up and i get better gas milage thank u. but i did get another minor problem. my antilock light sometime comes on and when it does my steering gets tighter any ideas?

 

[CyFi6]

The only reason to ever run "cold" is because it is easier to vaporize fuel when hot than when cold. So it is run richer when cold to keep it easy to light. Leaving it a little richer would only give you a little worse milage.

Thats why I would figure it would fail cold- to maintain decent drivability across the board (cold or warm). Oh well, now I know.

A side question- Does this mean that with the water temp sensor disconnected the TCCS will use o2 sensor feedback?

 

[jrot]

did you ever get this resolved?

 

[rap2chin]

yes i did Jrot the car puurs like a kitten now.
and Cyf16 no it wont my problem was. we got cold start injection with the coolant temperature sensor disconected the computer thinks the car is cold even when its hot whitch means it will keep dumping extra fuel in the motor through the cold start injector. and the result will be car runnin rich boggin out and idle like crap. one of the wires i belive the green one connects to the TPS sensor the brown to the TCCS makin it a OPEN CLOSE sensor. hope this helps anybody who might have that problem

 

[jetjock]

^ Amazing. And people wonder why I don't post much these days.

Cy: Of course it does. Think about it...